For example, as described in Patent Document 1 below, a gas turbine includes a compressor which compresses outside air and generates compressed air, a plurality of combustors which mix fuel with the compressed air, combust the mixture, and generate combustion gas, and a turbine which is driven by the combustion gas. The compressor includes a compressor rotor which is rotated about a rotational axis and a compressor casing which covers the compressor rotor. The turbine includes a turbine rotor which is connected to the compressor rotor and is rotated about the above-described rotational axis, a turbine casing which covers the turbine rotor, and an exhaust casing through which combustion gas which has driven the turbine rotor passes as exhaust gas.
The compressor casing, the turbine casing, and the exhaust casing are all formed in a tubular shape. The compressor casing, the turbine casing, and the exhaust casing are connected to one another by a bolt and a nut, and configure a tubular gas turbine casing.
Generally, the compressor casing, the turbine casing, and the exhaust casing all include upper half casings which form the upper side of the casing and lower half casings. The upper half casings and the lower half casings are connected to each other by bolts and nuts.